Description
Emerson DXP-L21ZNEB
Technical Specifications
- Product Type: Valve position monitoring transmitter
- Sensing Principle: Non-contact magnetic sensing
- Switch Output: SPDT contact output
- Supply Voltage: 24 VDC or 120 VAC
- Protection Class: IP67, NEMA 4X
- Operating Temperature: -40 °C to +85 °C
- Housing Material: Aluminum alloy
- Certification: ATEX, IECEx, SIL2 capable
- Mounting: Direct mount on valve shaft
- Switch Cycle Life: More than 1 million operations
Functional Features
- Non-contact magnetic sensing, no mechanical wear between sensor and actuator magnet.
- SPDT switch contact output transmits valve open and closed status.
- Explosion-proof housing for installation in hazardous explosive zones.
- IP67 enclosure resists dust, rain and water splash in outdoor plant environment.
- Simple on-site adjustment of switch trigger points.
- Anti-vibration structure adapts to pipeline vibration of process valves.
- No mechanical linkage wear, long service life and low maintenance requirement.
- Visual local position indicator on housing.
- Compatible with ball valve, butterfly valve and gate valve rotary shaft.
- Suitable for safety interlock valve position confirmation in SIS system.
Application Scenarios
- Oil & gas pipeline emergency shut-off valve position feedback
- Chemical plant on-off valve status monitoring
- Refinery process isolation valve remote indication
- Power plant water and gas isolation valve monitoring
- Offshore platform valve position detection in hazardous area
Material Composition
- Housing: Die cast aluminum alloy with epoxy coating
- Sensing unit: Hall effect magnetic sensor
- Actuator magnet: High performance permanent magnet
- Switch element: Sealed micro switch
- Sight window: Polycarbonate transparent window
- Sealing gaskets: Fluorine rubber corrosion resistant seals
Structural Characteristics
- Compact rectangular aluminum explosion-proof housing.
- Bottom mounting base directly couples to valve rotary shaft.
- Internal magnetic sensor detects magnet position fixed on valve shaft.
- Front sight window shows mechanical valve position indicator.
- Internal sealed switch chamber isolates electronics from process environment.
- Cable entry port for field wiring connection.
Working Principle A permanent magnet is fixed on the valve rotary shaft. When the valve rotates between open and closed position, the magnet rotates together with valve shaft. The internal magnetic sensor detects magnet position and triggers micro switch. The switch contact changes state to send valve open or closed digital signal to PLC or SIS system. Non-contact magnetic sensing eliminates friction and wear of mechanical lever linkage.
Installation Requirements
- Mount the transmitter directly on valve actuator shaft, align magnet and sensor correctly.
- Adjust trigger point after installation to ensure switch action at correct valve position.
- Use shielded field cable for signal wiring, install cable gland for sealing.
- Tighten all housing bolts to maintain IP67 enclosure integrity.
- Verify switch status by manually stroking valve full travel range.
- Ensure housing is properly earthed according to explosion-proof requirements.
- Keep magnet and sensor free from metal debris accumulation.
Usage Notes
- Do not disassemble explosion-proof housing in explosive hazardous area when powered.
- Avoid strong external magnetic field near sensor and magnet assembly.
- Check cable gland sealing periodically to prevent water ingress.
- Do not exceed rated contact voltage and current of internal switch.
- Clean metal debris around magnet and sensor regularly.
- Test valve position feedback signal after valve overhaul.
- Do not modify internal wiring or sensor assembly.
